Schuurmans-Stekhoven, James. “Measuring Spirituality As Personal Belief in Supernatural Forces: Is the Character Strength Inventory-Spirituality Subscale a Brief, Reliable and Valid Measure?”. Implicit Religion, vol. 17, no. 2, Aug. 2014, pp. 211-22, https://doi.org/10.1558/imre.v17i2.211.